A molder is known comprising a base, a lifter carrying pattern attachments and a casting box, and supporting columns carrying a pulsed-air head, a meter-filler and a filling frame, the meter-filler being spring-loaded against the filling frame and movable in the vertical direction into the internal cavity of the same; moreover, the device for filling the filling frame with mold-sand comprises a meter-filler spring-loaded against the filling frame and movable in the vertical direction into the internal cavity of the same, the meter-filler and the filling frame being provided with a drive for their translation, a gate being provided at the level of the upper surface of the meter-filler (see RF patent No. RU 2022684, Int. Cl. B22C 1/28, published on 15 Nov. 1994).
The method for the manufacture of casting molds realized by the above described molder comprises the following: the mold-sand is poured from a hopper into a meter-filler and a filling frame to further fill a casting box with the mold-sand, the rest of the last being kept in the filling frame, later the mold-sand is compacted by the pulsed-gas method, and the casting mold is re-compacted while moving the lifter up and displacing the remaining mold-sand from the filling frame into the casting box.
The use of the above described structures and of the method for manufacturing casting molds enables to increase productivity thanks to saving time and to combining operations. But the main drawback of the known technical solutions consists in the impossibility to provide efficient compacting of the mold-sand in the areas adjoining the casting box walls and the pattern plate, in particular in the narrow space between the patterns and the casting box walls, and in the casting box angles. The reason of the fact is a strong braking effect of friction against the casting box walls during the compacting by a pressing plate forcing the mold-sand out from the filling frame to the casting box as viewed from the drag portion of the mold. In this case, the distribution of the mold-sand compaction around the mold is not favorable and leads to a bad technology: the maximum is at the drag portion, and the minimum at the pattern plate. The combination of so called “upper” compaction with the pulsed action onto the mold-sand with compressed air somewhat reduces but does not completely eliminate this effect.
A method for the manufacture of sand molds is known, which comprises the steps of: compacting the mold-sand by a compressed gas impulse and additional mechanical pressing by upper compaction with a latticed pressing plate, and a device for realizing the mentioned process is known, comprising a base, a lifter, a casting box, a pulsed-gas head mounted fixedly above the casting box and linked to a system of compressed gas supply, a latticed pressure plate mounted in the lower part of the pulsed-gas head with the possibility of a reciprocal motion with regard to the same in the direction of the casting box, provided by a separate piston drive (see U.S. Pat. No. 3,807,483, Int. Cl. B22C 15/28, published on 30 Apr. 1974).
Nevertheless, the above mentioned method and device provide the mold-sand compacting in the casting box with the same drawbacks as in the previous case. What is more, the existence of a separate piston drive makes the structure more complicated and requires additional energy expenditures, and the static pressure of the plate to the upper surface of the mold-sand is less efficient than the plate compression in a dynamical regime. The mechanical compacting after the end of the pulsed-gas compaction is less efficient as well than when it is performed simultaneously with the last, while the mold-sand is in a fluid state.
A method for the manufacture of casting molds is known, which comprises the steps of: filling with mold-sand the casting box and the filling frame containing patterns located inside them, mounted on a pattern plate, leveling of the mold-sand surface by moving a multi-position (piston-type) pressing plate together with a prominent scraper fixed on the same, into a position above the casting box, complete lifting of the pattern plate in the filling frame, the mold-sand being moved without its compaction from the frame to the casting box and from the casting box to the free space above the same, pulsed-air pre-compacting of the mold-sand by the effect of the compressed air passing through the moving multi-position pressing plate, and active (full) compressing from above with the compressing elements of the controlled-pressure pressing plate, with the following pulling-through of the pattern, the mold-sand being poured into the casting box and the filling frame under the effect of gravity, and a device realizing said process is known as well, comprising a base, a pressing cylinder, a molding table with a carrier of the pattern plate with patterns, a filling frame with a casting box mounted on the last, a pulsed-air head located above the molding table and linked to a system of compressed air supply, a movable pressing plate with a multi-position (piston-type) pressing element, the filling frame being built-in into the molding table and made with the possibility to place molded casting boxes onto the frame and to take them away from the same, the pattern plate with patterns being placed with the possibility of a reciprocal motion in the cavity of the filling frame, and the pressing cylinder being placed with the possibility to apply force to the movable pattern plate (Advertising brochure of the company “Savelli”, p. 12, November 2009).
The above described method and device remedy only in part the main drawbacks of the previous analogs: not rational and not uniform distribution of the mold-sand compaction.
The closest to the technical solution according to the present invention, as to its technical nature, are a method for filling a filling frame and a casting box with mold-sand, and for pulsed compacting of the mold-sand by compressed gas with a simultaneous dynamical re-compacting of the upper layer of the mold-sand with a movable latticed pressing plate moving under the effect of the energy of a compressed gas impulse, as well as a device for compacting the mold-sand, comprising a base, a lifter carrying a filling frame and pattern attachments, a casting box, a pulsed-gas head fixedly mounted above the casting box and linked to a system of compressed gas supply, a latticed pressing plate mounted in the lower part of the pulsed-gas head with a possibility of a reciprocal motion relative to the pulsed-gas head in the direction of the casting box, the pressing plate being linked to the pulsed-gas head via elastic elements made in the form of springs or cables, besides, the device is provided with a cylinder mounted in the pulsed-gas head with the possibility of free contact of its rod with the pressing plate (see the RF patent No. RU 2159165, Int. Cl. B22C 15/28, published on 20 Nov. 2000).
Said method and device increase the efficiency of the mold-sand compacting by a compressed-gas impulse and enable a better mold-sand 5 density distribution around the whole volume of the mold compared to the previous case.
Nevertheless, they show the same drawbacks of the compacting from above, characterizing two previous cases described, which represents the reason hampering a wide use of said invention. The dynamic character of compacting with a latticed element does not modify the nature of the image of problems characteristic for the compacting from above and that of the not rational mold-sand compaction distribution around the volume of the mold.